ASVCP Young Investigator Awards

Heather Priest, DVM, Cornell University

TRANSFERRIN RECEPTOR EXPRESSION IN CANINE NON-HODGKIN'S LYMPHOMA. H. L. Priest, T. Stokol, S. McDonough, H. Erb, P.J. Fisher. College of Veterinary Medicine, Cornell University, Ithaca, NY.
   Transferrin, the major plasma iron transport protein delivers iron to rapidly dividing cells by binding to a specific receptor, the transferrin receptor 1 (TfR1, CD71). Proliferating neoplastic cells require large amounts of iron and thus express high levels of TfR1. In studies in human patients with non-Hodgkin’s lymphoma (NHL), TfR1 expression has been shown to correlate with both tumor grade and prognosis, making the receptor a potential diagnostic and prognostic marker in this disease. We hypothesize that TfR1 is expressed in neoplastic lymphocytes in canine NHL and that expression relates to tumor grade. In order to test this hypothesis we examined the expression of TfR1 by immunohistochemistry using an antibody directed against the cytoplasmic domain of the human receptor. Archived cases of histologically confirmed canine NHL diagnosed at the Cornell University Hospital for Animals from 2007 to 2008 were re-classified according to World Health Organization criteria. Immunoreactivity for TfR1 was quantified (percentage of positive staining cells and intensity of staining) in formalin-fixed, paraffin-embedded sections. To date, 18 lymph node biopsies have been examined, including 10 B cell lymphomas (7 high-grade and 3 low-grade) and 8 T cell lymphomas (6 high-grade and 2 low-grade). Using non-parametric statistics, high-grade tumors had significantly (p <0.05) higher expression of TfR1 (median, 76 – 100% positive cells, moderate intensity), compared to low-grade tumors (median, 26– 50% positive cells, weak intensity). No significant difference in TfR1 immunoreactivity was detected between T cell and B cell neoplasms. Based on these preliminary results, TfR1 expression appears to correlate with tumor grade in canine NHL. Further studies are needed to determine the prognostic value of this marker. (Reprinted with permission from Vet Clin Pathol, 37 [supplement], 2008, http://www.blackwellpublishing.com/vcp [3], 2008).